<?xml version="1.0" encoding="utf-8"?>
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>Drag and drop and vertical scrolling: dropping block element onto canvas inside scrollable container</title>
<style type="text/css">
div[draggable]
  {width:20px;
  height:20px;
  background-color:green;}
p + div
  {height:100px;
  width:150px;
  overflow-y:scroll;}
canvas
  {display:block;
  margin-top:100px;}
</style>
<script type="application/ecmascript">
function paint(color)
  {var canvas = document.querySelector('canvas'),
  c = canvas.getContext('2d');
  c.fillStyle = color;
  c.beginPath();
  c.moveTo(0,0);
  c.lineTo(100,0);
  c.lineTo(100,100);
  c.lineTo(0,100);
  c.closePath();
  c.fill();}
function start(event)
  {event.dataTransfer.effectAllowed = 'copy';
  event.dataTransfer.setData('text/plain', 'green');}
</script>
</head>
<body onload="paint('gray')">
<div draggable="true" ondragstart="start(event)"/>
<p>You should be able to drag green box above to the gray canvas at the bottom of scrollable container (dragging towards the bottom edge triggers scrolling). Canvas should be repainted to match dropped color.</p>
<div>
  <canvas width="100" height="100" ondragenter="event.preventDefault()" ondragover="return false" ondrop="paint(event.dataTransfer.getData('text/plain'))">Canvas</canvas>
</div>
</body>
</html>
